Mercaptopurin versus Azathioprine: anyone else swapped from Aza to 6 MP?

[Bryonyboo]

I am due to start on mercaptopurin ( once I finally get through the fight to get it prescribed ). I was previously on Azathioprine for many years, but found eventually it made me tired and nauseous. I have been off it since my fistula surgery last year, but my specialist is keen to keep everything in remission so thinks 6MP may be better
Has anyone else swapped from Aza to 6 MP and have the side effects been less or better? Just curious , I know we are all different but would love to know your experiences.
I also have humira every 2 weeks